LED Lamp Driver Voltage Sensing for Incandescent Dimmer Compatibility
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Solution Overview
Problem
Conventional dimmer switches designed for incandescent lamps are not compatible with LED lamps, as LEDs are current-driven devices, whereas dimmer switches control light intensity by adjusting voltage, leading to fixed light output in LED lamps when connected to conventional dimmer wiring configurations.
Innovation Solution
An LED lamp system that senses input voltage and adjusts the forward current of LEDs to control light intensity, allowing it to be used with conventional dimmer switches by generating a dimming factor signal based on phase angle switching, and providing galvanic isolation between AC input voltage and LED elements, enabling the LED lamp to mimic incandescent lamp behavior for dimming purposes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional dimmer switches are used to control LED lamps, then compatibility with existing wiring is improved, but light intensity control capability deteriorates because LEDs are current-driven while dimmers control voltage
Solution Approach 1:
The patent introduces an intermediary circuit between the conventional dimmer switch and the LED lamp. This intermediary circuit converts the voltage control signal from the dimmer into appropriate current control for the LEDs, enabling compatibility with existing wiring while maintaining proper light intensity control. The intermediary acts as a bridge that translates between the voltage-driven dimmer interface and the current-driven LED load.
2Device complexity
If voltage control is used for LED dimming, then simplicity of control circuit is improved, but precision of light intensity adjustment deteriorates due to the non-linear current-voltage characteristics of LEDs
Solution Approach 1:
The patent changes the control parameter from voltage to current. By controlling the forward current through the LEDs rather than the voltage applied to them, the system achieves precise light intensity adjustment. This parameter change accounts for the non-linear current-voltage characteristics of LEDs, where small voltage changes can cause large current variations, thereby improving control precision.
3Reliability
If conventional LED drivers are used with dimmer switches, then galvanic isolation is maintained, but dimming functionality is lost due to fixed current regulation
Solution Approach 1:
The patent makes the LED driver dynamic by enabling it to vary its output current in response to dimmer control signals. Instead of maintaining fixed current regulation, the driver dynamically adjusts the current level to achieve dimming functionality. This dynamic behavior allows the driver to respond to user input while maintaining galvanic isolation through its inherent design.
Data Source
AI summary
An LED lamp is provided in which the output light intensity of the LEDs in the LED lamp is adjusted based on the input voltage to the LED lamp. The LED lamp comprises one or more LEDs, and an LED driver configured to receive an input voltage and provide regulated current to said one or more LEDs, where the LED driver is configured to adjust the regulated current to said one or more LEDs according to the input voltage to adjust the output light intensity of said one or more LEDs. The LED lamp can be a direct replacement of conventional incandescent lamps in typical wiring configurations found in residential and commercial building lighting applications that use conventional dimmer switches that carry out dimming by changing the input voltage to the LED lamp.